FLIGHT AVAILABILITY AND DISTANCE: DOMESTIC

Frequency of aircraft departures, the number of connections required
for a single trip, and the match between available flights and travelers'
desired origin and destination points are all important determinants of
scheduling convenience. Because data on connections are currently not
available in a suitable format, flight stage length is used here to supplement
the information on departures.

Flight stage length is the distance between take-off airport and landing
airport. If the mix of origin and destination points are held constant,
then an increase in flight stage length implies fewer connections are
required for a trip and, therefore, higher quality of air passenger services.

The key relation is that departures and flight stage length will tend
to move in opposite directions when changes are due to changes in the
number of connections. For example, a trip from city A to city B with
a connection in city C will have two departures, but generally a shorter
average flight stage length, than the direct flight from A to B with a
single departure.

Domestic Flight Availability

Apr-01

Apr-02

Revenue aircraft departures (thousands)

703

649

Revenue aircraft departures percent change from same month previous year

2.93

-7.68

Flight stage length (miles)

691

683

Flight stage length percent change from same month previous year

1.92

-1.16

NOTES: The current value is compared to the value from the same period
in the previous year to account for seasonality.

The data have been adjusted to have a standard 30-day month by multiplying
the data for each month by the ratio: 30/(actual days in month).

The data do not include international flights by U.S. domestic carriers
or domestic flights by foreign carriers.

The dramatic changes in the September 2001 data reflect the impact of
the terrorist attacks on Sept.11, 2001, on aviation, including several
days in which commercial air operations were suspended.

Alaskan carriers that began reporting T100 data in January 2002 are excluded
from this report to retain comparability for comparisons with the previous
year.

SOURCE: U.S. Department of Transportation, Bureau of Transportation Statistics,
Air Carrier Traffic Statistics Monthly, July 2002.